Background - Individuals who experience the symptoms of acute myocardial infarction (AMI) often delay hours or even days before seeking medical treatment. Median prehospital delay times (i.e., between the onset of cardiac symptoms and arrival at the hospital) have been documented to be 2.0 to 6.0 hours in numerous studies conducted over the past three decades. Such delays result in significant morbidity and mortality. Purpose - We propose a randomized experimental trial to determine whether a one-to-one education and counseling intervention delivered specifically to patients with documented ischemic heart disease will 1) reduce prehospital delay, 2) increase 911 use, and 3) increase aspirin use in those patients who experience AMI symptoms. Other aims to be tested relate to hypothesized changes in resource utilization; knowledge, attitudes, and beliefs about heart disease and AMI symptoms; and perceived control and anxiety. The effect of various sociodemographic characteristics and means of health care payment on prehospital delay will also be tested. Methods - 5,400 patients with documented ischemic heart disease will be randomized to the experimental intervention or to a care-as-usual control group at six participating sites. The intervention group will receive face-to-face counseling about the symptoms of AMI and the importance of seeking treatment early, as well as 911 and aspirin use. They will also receive telephonic reinforcement of the intervention at one-month follow-up. Data will be collected at baseline, immediately following the intervention, 3, 12, 24 and 36 months. Instruments to be used include the Response Questionnaire (knowledge, attitudes and beliefs), Cardiac Control Index (perceived control), Brief Symptom Inventory Anxiety Subscale, and the Resource Utilization Interview. Prehospital delay, 911 use, aspirin use and resource utilization will be evaluated by means of medical record review and patient interview. It is anticipated that approximately 3% of patients will experience AMI symptoms annually. Analyses. Standard multivariate and repeated measures analysis of variance techniques will be used to test study hypotheses. Significance - All previous interventions have focused on educating e public using mass media, with disappointing results. This study will be the first to test the effectiveness of a one-to-one intervention to reduce prehospital delay. The proposed intervention, if effective, could result in significant improvement in morbidity and mortality of patients with heart disease.